Slat monitoring system

Abstract

A system for determining whether the relative rate of deployment of all the slats (11) extending from a leading edge (12) of an aircraft wing (10) is the same as a predetermined relative rate of deployment is disclosed. Each slat includes at least one slat deployment mechanism that includes a drive pinion (8) drivingly coupled to each slat and a rotary actuator (14) having an output shaft (20), the output shaft being driven by a common input drive shaft (13) via the rotary actuator and being coupled to said drive pinion. The system of the invention comprises a sensor (21) associated with each rotary actuator to generate a signal indicative of the rate of rotation of its corresponding output shaft and to supply that signal to a controller (23). The controller is configured to analyse the signals supplied by the sensors and to generate an alarm signal if a relative rate of rotation of all the output shafts differs from a predetermined relative rate of rotation. A method is also disclosed.

Description

[0001]The present invention relates to a slat monitoring system and, in particular, to a system for determining whether the relative rate of deployment of all the slats extending from a leading edge of an aircraft wing is the same as a predetermined relative rate of deployment, within a defined tolerance. A method of determining whether the relative rate of deployment of all the slats extending from a leading edge of an aircraft wing is the same as a predetermined relative rate of deployment, within a defined tolerance, is also disclosed.BACKGROUND[0002]Aircraft need to produce varying levels of lift for take-off, landing and cruise. A combination of wing leading and trailing edge devices are used to control the wing coefficient of lift. The leading edge device is known as a slat. On larger aircraft there may be several slats spaced along the wing edge. During normal flight the slats are retracted against the leading edge of the wing. However, during take-off and landing they are de...

AI Technical Summary

Benefits of technology

[0009]Reference is made to the relative rate of deployment as being substantially the same and to the generation of an alarm signal in the event that the detected relative rate of rotation differs from a predetermined relative rate of rotation. However, it will be appreciated that small differences in the detected and predetermined relative rates of rotation are acceptable and may not trigger an alarm signal. These small differences are caused by operational and manufacturing tolerances and the system may be configured to make allowance for these to prevent inadvertent generation of an alarm signal when the difference between the detected rate and the predetermined rate is very small.

[0013]The encoder disc may have a first portion that extends radially from the output shaft and a second portion that extends in an axial direction from said first portion, spaced from said output shaft on which the disc is fixed. The axially extending portion may then be located between the light source and the detector and is the portion of the encoder disc that includes said plurality of spaced light transmissive and opaque regions to permit and prevent, respectively, a beam of light emitted in a radial direction by the light source from reaching the detector as the disc rotates together with said output shaft.

[0017]Preferably, the inner and outer discs include sealing elements to prevent ingress of contaminants into said space between said discs.

Problems solved by technology

However, it will be appreciated that small differences in the detected and predetermined relative rates of rotation are acceptable and may not trigger an alarm signal.

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